Process of making metallic films or flakes.



- UNITED s ArEs P TENT. OFFICE;

' THOIAS A. EDISON, OF LLEWELLYN PARK, ORANGE, NEW JERSEY, ASSIGNOR TO EDISON STOR E BATTERY COMPANY, OF WEST ORANGE, NEW JERSEY, A CORPORA- TION OF NEW JERSEY.

PROCESS OF MAKING METALLIC FILMS OR FLAKES. V

Specification of Letters Iatent.

Patented 0a. 12, 1909.

936,525. In Drawing. Application filed January 18, 1907. Serial No. 353,002.

To all whom it my concern:

Be it known that I, THOMAS ALVA EDISON, a citizen of the United States, residing at Llewellyn Park, Orange, in the county of Essex and State of New Jersey, have invented a certain new and useful Process of Makin Metallic Films or Flakes, of which the fo owing is a description.

My invention relates to an improved process of makin metallic films or flakes, and

particularly fiakes of metallic cobalt or metallic nickel or cobalt-nickel alloy, for use in the make-u of the positive electrodes of storage batteries of the Edison type. As I have previously indicated, flakes of metallic cobalt or cobalt-nickel alloy are peculiarly fitted for use, owingto the high character of the contact which will be afforded for the particles of active'material, such as nickel hydroxid, as well as the permanency of the flakes under the effect of electrolysis. In Letters Patent No. 821,626 dated May 29,1906, I describe a process for this purpose in which the flakes are formed. by-

depositing electrolytically upon a cathode layers or of a soluble metal alternating with successive films of the desired metal (cobalt or nickel or cobalt -vnickel) aft-er which the soluble metal is dissolved, so as 30 to result in the separation and segregation of the cobalt or nickel or cobalt-nickel films. In the patent referred to, I describe the use of zinc as a suitable solublemetal, and I describe the breaking up or sizing of the cobalt or nickel or cobalt-nickel fiakes by means of a screening operation.

My present invention relates to an im- 7 provement on the process described in said patent by which flakes of cobalt or nickel or cobalt-nickel can be secured which will be very much smoother, of more uniform thickness and more coherent than when zinc is used, and which flakes will also be more uniform in size than when sub-divided by a screening operation. I

To this end the invention consists, broadly speaking, first. in making use of copper as the soluble metal on' which the films of cobalt or nickel, or cobalt-nickel are deposited, and second, in cutting up the compositestrips or sheets to the required size after separation of the same from the cathode.

The invention also contemplates details of procedure, all as will be more fully hereinafter described and claimed.

In carrying my invention into effect, I

proceed substantially as follows: The cathode consists of a plate or cylinder of polished copper, preferably nickel-plated, and which may be conveniently rotated during the plating and subsequent operations, as I describe in my application for Letters Patent filed October 12, 1905, Serial No. 282,380. The cathode is first'rubbed with graphite so as to polish the surface thereof and permit the effective separation of the deposited composite sheet. 7 I first-introduce the cathode in acopper plating bath employing any'suitable copper salt, such as the sulfate thereof with metallic copper anodes and deposit a thin layer or film of copper on the cathode, as will be understood. Such a copper layer will be extremely smooth and coherent and in this respect very superior to zinc. The

cathode is now washed and then immersed in a cobalt or nickel or cobalt-nickel bath,

the solution used being preferably an ammo-- nium sulfate solution of the metal or metals to be plated, and anodes of cobalt or of nickel or of cobalt and nickel being employed. In the latter case, the anodes and'the depositing current will be so regulated as to secure the desired relative deposit of the two metals. When the cobalt or nickel, or cobalt-nickel film has been thus deposited on the copper film, the cathode is agaiuwashed, returned to the copper bath and a second layer of copper is deposited on the cobalt or nickel or cobalt nickel 'film. After washing, a second .film of cobaltor nickel or cobalt-nickel is deposited on the second copper film, and these operations are continued until a sufficient number of layers of copper and cobalt or nickel or cobalt-nickel are secured. The composite sheet thus obetained on the cathode is easily stripped from the same by cutting the sheet longitudinally, so as to perin-a very strong solution sists in electrolytically type, into squares or. other forms, the dimen I sions of which in length and breadth determine the ultimate size of the flakes to be produced. Ordinarily, each flake will be about of an inch square. At this stage of the method, I will obtain a great number of very small squares or bodies each formed of successive and alternating layers of copper and cobalt or nickel or cobalt-nickel, as will be understood. It now becomesnecessary to dissolve the copper Without afiecting the co balt or nickel or cobalt-nickel flakes, thereby eliminating the copper and separatin the flakes desired. This is preferably e ected by soaking the sub-divided composite bodies of cyanicl of potassium, and agitated at times during the treatment. The effect of the cyanid is to dissolve the metallic copper, without appreciably affecting the cobalt or nickel or cobaltnickel, thus freeing the flakes of cobalt or nickel or cobalt-nickel and effectively separating the same. These flakes may now be used directly in the make-up of the battery electrodes 01' they may be first annealed in hydrogen before such use. In applying the cobalt or nickel or cobalt-nickel flakes to the active particles, I prefer to makeuse of the process described in my patent dated December 25, 1906, No. 839,371, wherein the active particles are first coated with a sticky material, such as molasses or glucose, after which the conducting flakes are added, and will be caused to adhere to the surface of the active particles to thereby coat the same in the most effective manner.

Having now described my invention, What I claim as new and'desirc to secure by Letters Patent is as follows 1. The process ofmaking films or flakes of cobalt or nickel or cobalt-nickel, which consists in electrolytically depositing on a suitable cathode a layer or film of copper, then in depositing on the copper film a layer or film of cobalt or nickel or cobalt-nickel, and in finally dissolving the deposited copper to free the film of cobalt or nickel or cobaltnickel, substantially as set forth.

2. The process of making films or flakes of cobalt'or nickel or cobalt-nickel, which condepositing upon a suitable cathode a layer or film of copper, then in depositing on the copper a layer or film of cobalt or nickel or cobalt nickel, then in separating the composite sheet fromthe cathode and in finally posited copper film to free the film of cobalt or nickel or cobalt nickel, substantially as set forth.

dissolving the de- 3. The processof making films or flakes of cobalt or nickel or cobalt-nickel, which consists in depositing upon a. layer or film of copper, then in depositing upon the copper film a. layer or film of cobalt or nickel or cobalt-nickel, then in separating the composite sheet from the cathode, then in cutting up the composite sheet into bodies of the ultimate shape and size and in finally dissolving the copper to free the deposited cobalt or nickel or colm-lt-nickel, sl'ibstantially as set forth. r r

4. The process of 'making'films or flakes of cobaltor nickel or cobalt-nickel, which consists in depositing upon a suitable cathode a layer or film of a soluble metal, then in depositing on the soluble film a layer or film of cobalt or nickel oncobalt-nickel, then in separating the composite sheet from the cathode, then in cutting up. the composite sheet into bodies of the ultimate shape and size and in fina lly dissolying the soluble metal to' free the flakes of cobalt or nickel or cobalt-nickel, substantially as set forth.

5. The process .of making films or flakes of cobalt. or nickel or cobalt-nickel, which con' slsts in depositing upon' a suitable cathode successive and alternating layers of copper a suitable cathode and cobalt or nickel or cobalt-nickel, and in finally dissolving the copper to freethe films of cobalt or nickel or cobalt-nickel, substantially as set forth.

6. The process of ma king filins'or flakes of c0balt or nickel or cobalt-nickel, which consists in applying graphite to a suitablecathode, then in depositing a layer or film of copper thereon, then in depositing on the copper film a layer or film of .cobalt or nickel or cobalt-nickel, and in finally dissolving the copper to free the film of cobalt or nickel or cobalt-nickel, substantially as set forth. 7

T. The process of making films or flakes of cobalt or nickel or cobaltaiickel, which consists in depositing upon a suitable cathode a layer or film of copper, then in depositing a layer or film of cobalt or nickel or cobaltnickel on the copper film, and in finally subjecting the composite sheet so formed to the action of a cyanid of an alkali. to dissolve the copper and free. the deposited cobalt or nickel or cobalt-nickel, substantially as set forth.

This specification signed and witnessed this 17th ,day of January 1907.

THQS. A. EDISON. Witnesses:

FRANK L. Drnn, ANNA R. KLEI-IM. 

